Aug
11
2018

HPV Testing For Cervical Cancer

HPV testing for cervical cancer is more sensitive than the traditional Pap test. For years physicians recommended the traditional Pap test once a year to prevent cancer of the cervix. But a few years ago a new cervical cancer screening test, namely the HPV test made the news. It stems from the observation that cancer of the cervix develops in 99.7% of women who test positive for the HPV virus. There are many types of HPV, here we are interested in the few subtypes that produce cancer (carcinogenic HPV virus).

Transmission of the HPV virus between men and women

The human papilloma virus transmits from males to females through bisexual contact. The problem starts when he develops HPV lesions on his penis. Without him wearing a condom, the contact with her cervix during sex can transmit HPV to her cervix. Both partners are not aware of the transmission of that virus, as it does not cause any symptoms. HPV invades the superficial skin layer of the cervix in the woman. In the man HPV will invade the skin of the glans of the penis. After certain incubation time it causes transformation into cervical cancer in the woman. Strangely enough it does not cause cancer in the male. However, in both sexes HPV virus is in the mucous membranes and can contaminate the other sex’s genital.

A recent study comes from UBC Vancouver, British Columbia, which compared the Pap test with HPV testing.

Details of the Vancouver study on HPV testing for cervical cancer

On July 3, 2018 this study appeared in the medical journal JAMA.

19,009 women were part of this randomized clinical trial. With HPV testing only 2.3 cases per 1000 women of early cervical cancers were present four years later. Using the traditional Pap test this figure was 5.5 cases per 1000 women after 4 years. 224 clinicians participated in this study. Women were recruited for this study from January 2008 to May 2012. Follow-up took place till Dec. 2016. The participating women in this study were 25 to 65 years of age.

In 2017 in the US there were still 12,820 women in the United States who got cancer of the cervix. Approximately 4210 are dying from this disease every year. Many women do not like to take the Pap test or the HPV testing. There are compliance problems with either one of these tests.

Significance of this trial regarding HPV testing for cervical cancer

The newer HPV testing was superior to the regular Pap test. The HPV test was more sensitive and resulted in much lower cancer rates after 4 years of follow-up. Every woman would have an HPV test every 4 years. In this case we likely would see cervical cancer go to the bottom of cancers that kill women. The reason for that is that HPV testing and colposcopy pick up cancers much earlier. This leads to a more effective treatment of cervical cancer. After 4 years much less cancer of the cervix was found when the researchers tested again using HPV testing.

Implications of HPV testing for cervical cancer

In third world countries

Many 3rd world countries do only the HPV testing. At the time when this decision was made, it was unknown that they had actually chosen the better method to test for cancer of the cervix. Now this trial reassures all the health care providers in 3rd world countries that they should continue with the program, and they only have to do the test every 4 years, not every 2 years, which makes it even more cost effective.

Implications for the US

In the US so far the recommendation was to do both the regular Pap test and the HPV test simultaneously. This trial, however, says that this is not necessary. It would be better to use the more sensitive HPV test and abandon the more expensive and less sensitive PAP test. In 2012 a taskforce recommended to do the Pap smear in women age 21 to 65 every 3 years. The taskforce further recommended to women age 30 to 65 that they screen with a combo of cytology and HPV testing every 5 years. The lead investigator, Dr. Ogilvie said: “Offering women HPV [testing] for cervical cancer screening detects more precancerous lesions earlier, and also a negative HPV test offers more assurance that women will not develop precancerous conditions in the next four years,” she said. “This can mean that women may need less frequent screening but have more accurate results.”

What other doctors are saying about HPV testing for cervical cancer

Comments by Dr. Kathleen Schmeler

Dr. Kathleen Schmeler said that the study was “well-designed” and provided a much-needed comparison of Pap versus HPV testing. She is a gynecologic oncologist and at The University of Texas MD Anderson Cancer Center. She was part of the new research. Dr. Schmeler added: “The bottom line is that this could really potentially simplify how we screen women and have it be more effective and not quite as complicated and burdensome — and opens the door for doing just HPV testing, which is actually what’s currently recommended by the World Health Organization for countries that don’t have Pap testing capabilities,”

Comments by Dr. Stewart Massad

Dr. L. Stewart Massad Jr. is a professor of obstetrics and gynecology in the division of gynecologic oncology at Washington University School of Medicine. He wrote an editorial to the study in the JAMA. He wrote: “What will replace the Pap test? In 2012, the American Cancer Society endorsed co-testing with cervical cytology testing and HPV testing at 5-year intervals as the preferred strategy for screening women 30 to 65 years of age because this approach combines the sensitivity of HPV testing with the familiarity of traditional Pap testing,” He then went on to say: “However, the addition of cervical cytology testing adds little to the accuracy of HPV testing while increasing cost and false-positive results. In 2018, organizations that develop cancer screening guidelines are wrestling with whether to recommend replacing co-testing with primary HPV testing as the optimal screening strategy.”

Future dilemma

In view of all those comments the regulatory agents will have to come up with solutions for what is in the best interest of women for testing for cervical cancer.

HPV Testing For Cervical Cancer

HPV Testing For Cervical Cancer

Conclusion

A large randomized clinical trial in Vancouver, BC, Canada has compared screening methods for cancer of the cervix in women. Half of the subjects underwent screening by the newer HPV tests that checks for the presence of HPV virus. The other half received conventional screening by the Pap test (a cytological screening test.) The result was that the HPV test was more sensitive and resulted in less early cancer tests 4 years down the road. With the conventional Pap test there were more than double the amount of abnormal cells present 4 years down the road, which makes the Pap test less safe compared to the HPV test.

It appears from this trial that the Pap test is no longer a choice, except for colposcopy procedures that take care of early cervical cancers. But for screening in general HPV testing every 4 years is all what every women needs for her protection.

Related topics:

  1. Cancer rates increased in women.
  2. Catch cancer early.
  3. HPV testing was described in this blog in 2013: Low cost cervical cancer screening.

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Jul
21
2018

Frequent Flying Can Increase Cancer Rates

A review article from June 25, 2018 discusses that frequent flying can increase cancer rates. A study showed that cancer of the breast, cervix, skin, thyroid and uterus are about twice as common in female stewardesses than in women at large. Also, gastrointestinal system cancers including cancer of the colon, stomach, esophagus, liver and pancreatic cancers are more common. This observation was true in both male and female flying personnel who engage in frequent flying. This publication comes from a scientific paper published on June 26, 2018.

Study of flight attendants

Patients from the National Health and Nutrition Examination Survey (NHANES) served as a control for flight attendants. This control group consisted of 2729 patients; they were of a similar socioeconomic status as the flight attendants. In contrast there were 5366 flight attendants with much higher cancer rates than normally expected. Specifically breast cancer had a 1.51-fold higher frequency than the control group. Melanoma had a frequency of 2.27-fold in comparison to controls, and non-melanoma cancers had a cancer rate of 4.09-fold when compared to controls. Non-melanoma cancer cases include basal cell and squamous cell carcinomas.

Cancer rates in pilots

In a meta-analysis of various studies it became obvious that pilots had 20% more prostate cancer than a non-pilot control group. However their mortality was not higher than controls.

In an interesting study spanning over 60 years Icelandic airline pilots underwent an analysis for cancer development.

83 cancers were registered. The general population (non-pilots) served as controls.  There was an increase of 2.42-fold for all cancers compared to controls. Prostate cancer was higher in these pilots by 2.57-fold. Malignant melanoma had a 9.88-fold increase in pilots in comparison to controls. The basal cell carcinomas in these pilots were 3.61-fold more common than the rates in the controls. With regard to basal cell carcinomas of the trunk there were 6.65-fold more of them in comparison to controls.

The difference between the pilots and the general population was likely due to the higher exposure to cosmic radiation. This is what the authors concluded.

How does cancer develop?

There are several ways cancer can develop. One of the known cancer causations is ionizing radiation. We know a lot about this from the atom bombs of WWII in Japan. There were many more thyroid cancers in children than were normal following the dropping of the atom bombs.

But diagnostic CT scans and X-rays are not without risk of cancer development either. There is a lag period of 10 to 20 years and even longer. But after this time the higher cancer rate becomes measurable. A person who had a CT scan done as a diagnostic test in childhood will still have a 25% higher cancer rate 15 years later. This is how powerful radiation of the DNA of our cells is despite inherent repair mechanisms that fight back to keep things normal.

Single cancers versus multiple cancers

It is interesting that female stewardesses and male pilots came down with a mix of various cancers. There were skin cancers, breast cancers, cancers of the prostate and many gastrointestinal cancers. The numbers were not big enough to show statistical significance for leukemia also being a likely cause of cancer from cosmic radiation.

If cosmic radiation was going through the body randomly hitting various DNA strands in all cell types, which could explain why a random number of cancers develop in those cells that got the highest exposure. The ones who got above average cancer were stewardesses and pilots who were longest on their jobs. A variety of cancers would develop from various tissues. This is exactly what the studies have shown.

There are frequent flyers like business travelers and vacation seeking retirees who will also be at a higher risk of developing cancer. The more they fly, the higher the risk.

Other causes of cancer

Cosmic radiation is only one cause of cancer. There are many other causes of cancer. If you smoke heavily or abuse alcohol this can cause genetic mutations of cells that can develop into cancer. There is a pathway to cancer, which consists of initiation, promotion and progression. After those initial hurdles the cancer cell will multiply and start metastasizing into other areas of the body.

Carcinogens can damage the DNA of cells. In the case of pollution carcinogens enter the body through the air. But consuming processed meat and red meat has a proven link to cancer development as well, namely colon cancer.

Diverse factors all can cause cancer

Chronic inflammation from chronic infections is also carcinogenic. Chronic gastritis is caused by H. pylori. After years of infection with this pathogen stomach cancer can develop. Hepatitis viruses that are chronically present in liver cells can be the cause of liver cancer. Human papilloma virus (HPV) is the cause for the development of cancer of the cervix. The majority of cancer is caused from the environment or by poor life styles. Only 5 to 10% of cancers are inherited.

Tumor suppressor genes are important in terms of resisting the development of cancer. The TP53 gene produces a protein that interferes with the multiplication of cancer cells. Cancer cells in turn can produce a protein that interferes with TP53 function. The end result is that it will interfere with the body’s immune system to produce killer T cells. This way the cancer has the upper hand. There are some herbs that have shown anti-cancer effects, such as curcumin. http://www.askdrray.com/curcumin-and-cancer/. As I explain in this blog, there are absorption problems with curcumin presently. It is not yet primetime for curcumin, but it could be once the absorption problems are overcome. Nevertheless the research surrounding curcumin is interesting.

Frequent Flying Can Increase Cancer Rates

Frequent Flying Can Increase Cancer Rates

Conclusion

Several interesting studies have shown that stewardesses, pilots and frequent airplane travellers have a higher risk of developing cancer. Research groups have been careful to control these studies for lifestyle factors and other causes of cancer. Exposure to cosmic radiation is the common culprit that is behind this cancer causation. There was a multitude of cancers rather than one single type of cancer in pilots and stewardesses. This makes it more plausible that it is indeed cosmic radiation that caused the cancer increase. But cancer development is complex, and I have summarized this briefly here. It is important to be aware of all the possible causes of cancer. This allows you to minimize your exposure to carcinogens. We all get exposure to carcinogens from pollution. In addition we get exposure to cosmic radiation according to how much time we spend flying to holiday destinations or on business trips. Be safe and be informed!

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Dec
11
2016

Cancer Rates Increased In Women

A recent review of cancer rates worldwide shows that cancer rates increased in women. This by itself is alarming, but based on that data the rates likely will go up by 60% in the year 2030. The main reason is the smoking discrepancy among women and men. Men as a group have been smoking more than women. But women as a group are more and more embracing smoking. All of the negative health consequences of the last 3 decades for men are just starting to show now for women as well.

The World Health Organization explains it this way: in high-income countries like Australia, Canada, the US and Western Europe women smoke at nearly the same rate as men.

But in low and middle income countries women do not smoke as much as men do. For instance in China 61% of men are smokers, but only 4.2% of women are smoking. In Argentina 34% of men are currently smokers, which compares to 23% of women who smoke in this country.

When this gap will close, likely by the year 2030 women will have a whole host of diverse cancers, heart attacks and strokes caused by the smoking habit.

Some statistics and facts

High-income countries like Australia, Brazil, Canada, Israel and many northern and western European countries have a 5-year survival rate for breast cancer of 85%. In contrast the 5-year survival rates are 60% or less in low- and middle-income countries like South Africa, Mongolia, Algeria and India.

Cancer prevention measures can make a big difference later in life. Examples are hepatitis B vaccination, which will prevent liver cancer; vaccinating boys and girls against HPV, which will prevent cervical cancer in women; also having regular mammograms will detect breast cancer earlier and improve breast cancer survival rates.

Dr. Nestor Esnaola, surgical oncologist at Fox Chase Cancer Center at Temple University Hospital, Philadelphia, PA said that the cancer prevention methods just mentioned might not be available in developing countries. Instead of mammographies repeat breast self-examinations are more important there. Campaigns against smoking can be utilized in order to prevent cancer of the lungs, the throat and neck. And if colonoscopies are not available, stool samples can be tested for blood and hemoglobin to check for colon cancer.

Different cancer rates increased in women in different countries

There are different cancer types that make the top chart for different countries. For instance in 2012 breast cancer was on top of most countries worldwide as the number 2 killer behind heart attacks and strokes. But other cancers ranked fairly high as well as causes of death: colorectal, lung and cervical cancers.

Despite this trend there were other countries like China and North Korea that had a higher incidence of lung cancer rather than breast cancer. The cancer researchers stated that the reason for this is that the smoking rates are higher in these countries. As already pointed out in China more than ½ of the men smoke, but only a small minority of the women smoke. But women in China are exposed to high amounts of secondhand smoke in addition to environmental pollution, which still causes a lot of lung cancer in women who live in this environment.

In many African countries cervical cancer is very common. Women, who are HIV positive, have a 5-times higher rate of cervical cancer. Southern and eastern Africa where there are higher rates of HIV, have higher rates of cervical cancer.

More data about women’s cancer rates

The American Cancer Society has produced a report entitled “Global Burden of Cancer in women, current status, trends, and interventions”, which points out some interesting statistics.

The greatest numbers of cancer cases and deaths occur among women in Eastern Asia. The estimate for 2012 worldwide was for 1.7 million cancer cases and 1 million deaths in women. China dominated its region with 75% of all female cancer cases and deaths in the region. In North America cancer cases and deaths within the US comprise 90% of the region. The cancer cases and deaths in India make up about 65% of the region of South-Central Asia.

The top mortality rates are found in low to medium income countries, namely in Zimbabwe, Malawi, Kenya, Mongolia and Papua New Guinea.

The most frequently diagnosed cancers in women are breast, lung, and colorectal cancers in economically more developed countries. However, the statistics are different for less developed countries where the top three most diagnosed cancers are breast, cervix, and lung. Similarly the leading causes of cancer deaths for women in developed countries are lung, breast, and colorectal cancers. In developing countries the leading causes of cancer deaths for women is cancer of the breast, lung, and cervix.

Cancer frequencies for women in different countries

The American Cancer Society reports that breast cancer is the most common diagnosed cancer among women in 140 countries. Cervical cancer is most common in 39 countries, all of which are low to medium income countries. There are some countries where other cancer types are more common. For instance in China and North Korea lung cancer is more common among women, in Mongolia and Laos liver cancer, and in South Korea it is thyroid cancer.

The most common cause of death from cancer in women is breast cancer in 103 countries, cancer of the cervix in 43 countries and lung cancer in 27 countries. Other most common cancer deaths in women are in the following countries:

  • Stomach cancer: in Bhutan, Peru, El Salvador, Guatemala, and Tajikistan
  • Liver cancer: in Laos, Mongolia and The Gambia
  • Colorectal cancer: in Japan and Slovakia
  • Esophagus cancer: in Turkmenistan.

Prevention and early detection

Changing the risk factors could modify 20% of breast cancer mortality worldwide. Avoiding excess body weight, physical inactivity and reducing alcohol consumption could all significantly reduce breast cancer mortality. For instance, women with a body mass index of greater than 35.0 have a 1.6-fold higher risk of breast cancer and a 2.1-fold higher mortality rate from breast cancer than women with a body mass index of less than 25.0.

Regular breast cancer screening with mammography is another tool that will reduce breast cancer mortality as the cancer is diagnosed earlier and treated at an early stage where it can often be cured. The WHO recommends for those countries where mammography programs are established that screening should be done only every two years and only between the ages of 50-69 to avoid X-ray over exposure.

Early detection, like for any cancer is the key for successfully treating breast cancer. When the cancer is found early, surgical removal in healthy tissue (lumpectomy) often cures breast cancer. Unfortunately in low to medium income countries the cancer is often found too late, requires more invasive mastectomies and radiotherapy and has a lower survival rate than in developed countries.

Cervical cancer

Cervical cancer accounts for the 4th most frequently diagnosed cancer in the world. In 2012 there were 527,600 cases diagnosed worldwide and 265,700 deaths from cervical cancer occurred in the same year. 90% of cervical cancers occur in developing countries with India accounting for 25% of the total cases. The key in detecting cervical cancer is a regular screening program. In developed countries where this has been in place cervical cancer incidence has decreased by 80% in 4 decades. At the other end of the spectrum are countries like Uganda, Zimbabwe, and some countries of Central and Eastern Europe where cervical cancer rates have been climbing. The reason for the spread is that the human papillomavirus (HPV) is now more common and screening methods for cervical cancer are not in place. HPV 16 and 18 are the most common carcinogenic subtypes of the human papilloma viruses; they are responsible for 70% of cervical cancers worldwide. By vaccinating teenagers before they engage in sex is a powerful tool to interrupt the infectious spread of an important risk factor for cervical cancer.

Instead of the traditional Pap test from the past the new test that is used now is an HPV-DNA test, a cervical swab that will detect DNA from HPV directly. It is more sensitive than the traditional Pap test. If the HPV-DNA test is positive, the patient is sent to a gynecologist who will perform a colposcopy test, which is a microscopic exam of the cervix. The gynecologist can use several effective treatment methods like a loop electrosurgical excision procedure, laser ablation therapy, cryotherapy or conization for deeper cervical cancer lesions.

As with any cancer early detection and treatment is paramount with cervical cancer. In developed countries the 5-year survival rate is 60 to 70%. In India the 5-year survival rate is 46%.

Cancer of the lung

In 2012 there were 583,100 cases of lung cancer in women worldwide and 491,200 died from it. Lung cancer is the second leading cause of cancer death in women and the third most common cancer. The statistics of lung cancer reflect the tobacco epidemic. It takes about 20 to 30 years after widespread smoking begins in a country before the deadly statistics set in. The peak of the cancer epidemic and the heart attack rates occurs about 30 to 40 years following the peak of smoking in that population.

Lung cancer rates in women have lagged behind men, because women as a group have started smoking later. In places like Hong Kong, the United Kingdom,

Australia, and the United States women started smoking earlier, and they are in the process of declining their smoking habit or quitting. This is reflected in the new lung cancer cases and also in the lung cancer mortality rates. Sadly, in many countries of Europe and Latin America women started smoking much later and they are still increasing their lung cancer statistics and mortality rates. Lung cancer killed 1.1 million men and 0.5 million women worldwide in 2012. In addition it is estimated that there are 21,400 lung cancer deaths annually from second-hand smoke in non-smokers worldwide.

Beside smoking there are other risks causing lung cancer. The estimated risk for women to die in millions is: exposure to household air pollution, 1.6; outdoor air pollution, 1.4; second-hand smoke, 0.35; occupational risk factors, 0.10; and residential radon, 0.03.

Cancer Rates Increased In Women

Cancer Rates Increased In Women

Conclusion

Women are still in the midst of a global increase of cigarette smoking, which starts often with female teenagers. As long as the smoking rate goes up there will be more breast cancer, lung cancer and cervical cancer. The American Cancer Society provided a detailed review of various cancers and how they are still increasing worldwide, because nobody pays attention to preventative measures. A simple step to prevent cancer is to quit smoking. Another step is to engage in regular physical activity. Finally keeping your body mass index under 25.0 is a third step that can be done by adopting a Mediterranean diet.

There are several pockets within the developed countries where cancer rates are coming down, which is encouraging. The initial overview and the three examples given here, breast cancer, cervical cancer and lung cancer were thought to illustrate this complex topic.